Why does my simple application stop

Question

I am new to learning android development and I am following this tutorial to make a small application. I just changed a bit of code. and when I click the send button, i get a prompt saying "Unfortunately this My First App has stopped." Can somebody please tell me whatever is the matter.

I replaced the code given in the tutorial (here shown as a block comment in the code of second class), and replaced by the code which is here made prominent with comments containing *.

FIRST ACTIVITY: -

package com.practice.firstapp1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import com.practice.firstapp1.R;

public class MainActivity extends Activity {

    public final static String EXTRA_MESSAGE= "com.practice.fristapp1.MESSAGE";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    /** Called when the user clicks the Send button */
    /** Called when the user clicks the Send button */
    public void sendMessage(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText editText = (EditText) findViewById(R.id.id1);
        String message = editText.getText().toString();
        intent.putExtra(EXTRA_MESSAGE, message);
        startActivity(intent);
    }

}

LAYOUT OF FIRST ACTIVITY: -

CODE OF 2ND ACTIVITY: -

    package com.practice.firstapp1;

    import android.annotation.SuppressLint;
    import android.app.Activity;
    import android.content.Intent;
    import android.os.Build;
    import android.os.Bundle;
    import android.support.v4.app.NavUtils;
    import android.view.MenuItem;
    import android.widget.TextView;

    public class DisplayMessageActivity extends Activity {

        @SuppressLint("NewApi")
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_display_message);

            // Make sure we're running on Honeycomb or higher to use ActionBar APIs
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                // Show the Up button in the action bar.
                getActionBar().setDisplayHomeAsUpEnabled(true);
            }

            //Get the intent which invoked this activity and read its extra's data into the string named message.
            Intent intent = getIntent();
            String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

            TextView textView = (TextView) findViewById(R.id.text_view_2); //************
            textView.setText(message);//***********

            setContentView(textView);//***********
//The above three statements along with statements from its layout (which have been given *s in comments have been placed instead of the statements in the following block comment. Because I wanted to create the TextView in layout.xml and handle its work in code.

/*
    // Create the text view
    TextView textView = new TextView(this);
    textView.setTextSize(40);
    textView.setText(message);

    // Set the text view as the activity layout
    setContentView(textView);
*/

        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
            case android.R.id.home:
                NavUtils.navigateUpFromSameTask(this);
                return true;
            }
            return super.onOptionsItemSelected(item);
        }
    }

LAYOUT OF 2ND ACTIVITY: -



    
        android:id="@+id/text_view_2"    
        android:layout_width="wrap_content"    
        android:layout_height="wrap_content"    
        android:textSize="40sp" />

ANDROID MANIFEST FILE : -

Raghunandan · Accepted Answer

From your comments

I havn't done anything in the manifest file. I think it is done automatically when we are using eclipse.

Yes eclipse does add the activity to manifest if you create a new Android Activity.

Your manifest looks fine. Remove the below line

Edit 1 :

setContentView(textView);

activity_display_message.xml already has a textview and in your code you initialize your textView and set text. TextView already has a parent.

No need for setContentView(textView)

Why does my simple application stop

Answers (1)

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